Diversity and abundance of water birds in a subarctic lake during three decades

Permanent lenke

Åpne

Dato

2013

Type

Journal articleTidsskriftartikkelPeer reviewed

Forfatter

Klemetsen, Anders; Knudsen, Rune

Sammendrag

The numbers of divers, ducks, gulls, terns and waders in the 15 km2 oligotrophic lake Takvatn, North
Norway, were estimated six times during 1983-2012. Systematic mapping surveys were done by boat
within the first week after the ice-break in June. Twenty-one species were observed over the years and
12 were regarded as breeding on the lake. Red-breasted merganser Mergus serrator was the dominant
diving bird, with the estimated minimum number of breeding pairs varying from 15 to 39 among
the years. Black-throated diver Gavia arctica (1-3 pairs), tufted duck Aythya fuligula (2-15 pairs) and
common scoter Melanitta nigra (1-5 pairs) bred regularly, while velvet scoter Melanitta fusca (1-2) and
goldeneye Bucephala clangula (2-4) were found in some years and mallard Anas platyrhynchos (1 pair)
and wigeon Anas penelope (1 pair) in one year. Common gull Larus canus (6-30 pairs) and arctic tern
Sterna paradisaea (2-35 pairs) bred in all years. Common sandpiper Tringa hypoleucos (3-9 pairs) and
redshank Tringa totanus (1-4 pairs) were regular waders. Density variations of mergansers, gulls and
terns are possibly related to density variations of threespine stickleback Gasterosteus aculeatus, their
dominant fish prey. As predators and parasite hosts, the water birds are important links in the food web
of the lake.